<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <link type="text/css" rel="stylesheet" href="webjars/bootstrap/5.1.2/css/bootstrap.css"/>
    <script src="webjars/bootstrap/5.1.2/js/bootstrap.js">

    </script>
    <script src="webjars/jquery/3.0.0/dist/jquery.js">
    </script>
    <script>
        $(document).ready(function(){
           alert('已经引入了')

            var username =   $('#username').val()
            var password = $('#password').val()

            $('#btn').click(function(){
                var username =   $('#username').val()
                var password = $('#password').val()
                $.ajax({
                    url:''
                })
            })
        });

    </script>
</head>
<body>
<div>

    <label for="username">账号</label>
    <div class="input-group">
        <span class="input-group-addon" id="basic-addon3">请输入账号</span>
        <input type="text" class="form-control" id="username" aria-describedby="basic-addon3">
    </div>
    <label for="password">密码</label>
    <div class="input-group">
        <span class="input-group-addon" id="">请输入密码</span>
        <input type="text" class="form-control" id="password" aria-describedby="basic-addon3">
    </div>
    <button id="btn">点击我提交数据</button>
</div>


</body>
</html>